1. Technical Field
The present invention relates to capacitor devices, and more particularly to a capacitor having a diamond-like-carbon dielectric.
2. Discussion of Related Art
Structural capacitor functional material systems have been designed in order to store and retrieve large amounts of energy. It has been shown that a capacitor can be formed by laminating a sheet of paper about 40 μm thick between carbon fiber/epoxy prepreg sheets. The paper serves as a dielectric and the carbon fibers serve as plates of a parallel plate capacitor. Several kinds of paper and epoxy combinations have been tried as the dielectric, with ordinary paper being the only one that could be successfully used to produce a functioning capacitor.
The functional performance of the structural capacitor produced with paper as the dielectric is poor. The dielectric constant is low and the thickness is high so the capacitance per unit area is low; the dielectric breakdown is low (15 kV/mm) so the energy storage per unit area is only 0.11 J/mm2. Also, paper has poor strength so incorporating thick layers of paper into the carbon fiber/epoxy composite may cause a large deficit in structural performance.
Therefore, a need exists for a capacitor having an improved dielectric.